JP2021015124A - Temperature indicator - Google Patents

Abstract

To provide a temperature indicator with which it is possible to discolor an intended point by a temperature rise or drop and discriminate it and confirm whether or not a temperature rise or drop is attempted then, as the state before discoloration in no case returns.SOLUTION: Provided is a temperature indicator 1 comprising a reversible thermochromic layer 2 changing from colored to colorless and containing the same temperature-sensitive color-changeable color-memorization composition, with one in a colored state and the other in a colorless state. The perfect coloration temperature t1 of temperature-sensitive color-changeable color-memorization composition in the colorless state is higher than or equal to a perfect coloration temperature t1 of temperature-sensitive color-changeable color-memorization composition in the colored state, and the perfect color extinction temperature t4 of temperature-sensitive color-changeable color-memorization composition in the colorless state is higher than or equal to a perfect color extinction temperature t4 of temperature-sensitive color-changeable color-memorization composition in the colored state.SELECTED DRAWING: Figure 1

Description

The present invention relates to a temperature indicator. More specifically, the present invention relates to a temperature indicator due to a color change of the reversible thermal discoloration layer.

Conventionally, anti-counterfeit printed matter in which non-color-changing printing and heat-changing printing having the same or similar color tone as the non-color-changing printing are performed has been disclosed (see, for example, Patent Document 1).
The anti-counterfeit printed matter gives the same visual and tactile sensation as general-purpose printed matter at normal operating temperatures, is configured to make anti-counterfeit printing difficult to detect, and can be easily identified by discoloring the target location as the temperature rises or falls. It is composed of.
However, even if the anti-counterfeit printed matter can be easily identified by discoloring the target portion due to the temperature rise or fall, it returns to the color before the discoloration, so it cannot be confirmed whether or not the temperature rise or fall has been attempted. It was.

Microfilm of Jitsusho 59-87237 (Jitsukaisho 61-2964)

In the present invention, the target portion can be discolored and discriminated by the temperature rise or fall of this kind of anti-counterfeit printed matter, and then the color does not return to the color before the discoloration. Is intended to provide a temperature indicator capable of.

The present invention comprises a reversible thermochromic layer containing the same thermochromic color memorizing composition that changes color from colored to colorless, one in a colored state and the other in a colorless state, wherein the colorless state is temperature sensitive. The complete color-developing temperature t ₁ of the discoloring color memory composition is a temperature equal to or higher than the complete color-developing temperature t ₁ of the temperature-sensitive color-sensitive color memory composition in a colored state, and the temperature-sensitive color-sensing color memory composition in a colorless state. The complete decoloring temperature t ₄ of the object is a temperature equal to or higher than the complete decoloring temperature t _{4 of the} thermochromic color memory composition in a colored state, and the thermochromic color memory composition is a color density −. exhibit photochromic colored state and the colorless state indicates a hysteresis characteristic with respect to temperature curve, in the course of temperature increase from the colored state, begins decolorized to reach decoloring starting temperature t _3, higher than the temperature t ₃ completely vanishing It becomes completely colorless in the temperature range of the color temperature t ₄ or higher, and in the process of lowering the temperature from the colorless state, it starts to color when the color development start temperature t ₂ is reached, and the temperature is lower than the temperature t ₂ and the complete color development temperature t ₁ or less. A temperature indicator showing hysteresis characteristics that are completely colored in the region, or reversible heat containing the same thermochromic color memory composition that changes color from colored to colorless, one in a colored state and the other in a colorless state. A color-changing layer is provided, and the complete color-developing temperature t ₁ of the colorless state-sensitive color-sensitive color memory composition is a temperature equal to or higher than the complete color-developing temperature t ₁ of the temperature-sensitive color memory composition in a colored state. The complete decolorization temperature t ₄ of the thermochromic color memory composition in the colorless state is a temperature equal to or higher than the complete decolorization temperature t _{4 of the} thermochromic color memory composition in the colored state. thermochromic coloring color-memory composition, color density - exhibit photochromic colored state and the colorless state indicates a hysteresis characteristic with respect to temperature curve, in the course of temperature increase from the colored state, reach the decoloring starting temperature t ₃ then began to decoloring, become completely colorless state at high complete decoloring temperature t ₄ above temperature range than the temperature t _3, in the process the temperature decreases from the colorless state, it begins to color to reach coloring initiation temperature t _2, A temperature indicator showing a hysteresis characteristic in which a completely colored state is obtained in a temperature range of a perfect color development temperature t ₁ or less lower than a temperature t ₂ is required.

According to the present invention, the target portion can be discolored and discriminated by increasing or decreasing the temperature, and then the color does not return to the color before the discoloration. Therefore, it is highly practical that it is possible to confirm whether or not the temperature has been increased or decreased. A temperature indicator can be provided.

It is explanatory drawing which shows the discoloration behavior of the temperature-sensitive color-sensitive color memory composition used in this invention. It is a vertical cross-sectional explanatory view of one Example of the temperature indicator of this invention. It is a vertical cross-sectional explanatory view of another Example of the temperature indicator of this invention. It is a vertical cross-sectional explanatory view of another Example of the temperature indicator of this invention.

The present invention is a temperature indicator with a reversible thermochromic layer containing the same thermochromic color-memory composition that changes color from colored to colorless, one in a colored state and the other in a colorless state, or from colored to colorless. It is a temperature indicator having a reversible thermochromic layer containing the same thermochromic color memorizing composition in a colored state and a colorless state on the other hand.

The temperature-sensitive color-memory composition is described in JP-A-4-17154, JP-A-7-179777, JP-A-7-33997, JP-A-8-39936, and the like. The discoloration temperature is opposite to the case where the shape of the curve showing the hysteresis characteristic (ΔH _B = 8 to 50 ° C.), that is, plotting the change in coloring density due to the temperature change, raises the temperature from the lower temperature side than the discoloration temperature range. The color changes by following a path that is significantly different from the case of lowering from the high temperature side of the range, and the color is developed in the low temperature range below the complete color development temperature (t ₁ ), or the high temperature range above the complete decolorization temperature (t ₄ ). decolored state in is decolorized by [temperature range (substantially two-phase retaining temperature region) between t ₂ ~t _3] in heat-decolorizable with color-memorizing (heating certain temperature range, by cooling It is a reversible thermochromic composition (which develops color) (see FIG. 1).
The hysteresis characteristics in the color density-temperature curve of the thermochromic color memory composition will be described.
In FIG. 1, the vertical axis represents the color density and the horizontal axis represents the temperature. The change in color density due to temperature change progresses along the arrow. Here, A is a point indicating the concentration at the temperature t ₄ (hereinafter referred to as the complete decolorization temperature) at which the complete decolorization state is reached, and B is the temperature t ₃ (hereinafter, the decolorization start temperature) at which the decolorization starts. The point indicates the density at (referred to as), C is the point indicating the density at the temperature t ₂ (hereinafter referred to as the color development start temperature) at which color development starts, and D is the temperature t ₁ (hereinafter referred to as complete) at which the color development state is reached. It is a point indicating the density at (called the color development temperature).
Discoloration temperature region is a temperature range between the t ₁ and t _4, it is possible to exhibit any of the states of the colored state and the decolored state, between t ₂ and t ₃ is a region having a large difference in color density The temperature range of is the substantial discoloration temperature range.
Further, the length of the line segment EF is a measure indicating the contrast of discoloration, and the length of the line segment HG passing through the midpoint of the line segment EF is a temperature width indicating the degree of hysteresis (hereinafter referred to as hysteresis width ΔH). If this ΔH value is small, only one of the two states before and after discoloration can exist in the normal temperature range. Further, when the ΔH value is large, it becomes easy to maintain each state before and after discoloration.
The thermochromic color memory composition can selectively maintain either a color-developing state or a decoloring state over the entire color retention temperature range (t _3- t ₂ ), and color development starts. It has a normal temperature range between the temperature t ₂ and the decoloring start temperature t ₃ .
The normal temperature range is preferably in the range of 5 to 35 ° C. described in JIS Z 8703, and the color development state or the decolorization state can be selectively stored and retained at a general operating environment temperature. it can.
Further, as the temperature-sensitive color-sensitive color memory composition, the complete decolorization temperature t ₄ is 40 ° C. or higher, preferably 50 ° C. or higher, and the complete color development temperature t ₁ is 0 ° C. or lower, preferably −10 ° C. It is preferable to use the following because the color does not change due to body temperature during high temperature conditions such as summer or when handled, and does not change under low temperature conditions such as winter.

The thermochromic color memory composition is formed by forming a reversible thermochromic layer using a composition in a colored state on one side and a colorless state on the other side.
In the reversible thermal discoloration layer, the same composition in a colored state on one side and a colorless state on the other side is contained in a single reversible thermal discoloration layer, and the same composition is used to prepare a composition in one colored state. The reversible thermal discoloration layer containing the reversible thermal discoloration layer and the reversible thermal discoloration layer containing the other colorless composition may be laminated.
When laminating the reversible thermochromic layer, the reversible thermochromic layer containing the other colorless composition may be laminated on the reversible thermochromic layer containing the colored composition, or the colorless composition may be laminated. A reversible thermal discoloration layer containing a colored composition may be laminated on the reversible thermal discoloration layer containing the above.

The temperature indicator uses a temperature-sensitive color-changing color memory composition, one in a colored state and the other in a colorless state. Therefore, in the normal temperature range, only the color of the thermochromic color memory composition in one of the colored states is visually recognized.
When the mixture is heated from this state, the thermochromic color-memory composition in the colored state is decolorized, and in the normal temperature range, each thermochromic color-memory composition is visually recognized as a colorless state.
Cooling is required to bring the thermochromic color memory composition into a colored state from this state, but the cooling causes both the thermochromic color memory compositions to be in a colored state, and each thermochromic color memory The color in which the sex composition is mixed is visually recognized.
Therefore, since one of the initial temperature-sensitive color-memory compositions does not return to the anti-counterfeit medium before the color change in the color-developed state, it is possible to confirm whether or not the temperature has been increased.
The complete color-developing temperature t ₁ of the thermochromic color-memory composition in the decolorized state is desired to be a temperature equal to or higher than the complete color-developing temperature t _{1 of the} thermochromic color-memory composition in the color-developed state. It is easy to express the effect of. Further, even if the complete color development temperature t _{1 of the} thermochromic color memory composition in the decolorized state is less than the complete color development temperature t _{1 of the} thermochromic color memory composition in the color development state, the temperature difference is large. If the temperature is 3 ° C. or lower, the desired effect can be exhibited.
Further, when cooled from the initial state, the thermochromic color memory composition in the decolorized state developed a color, and in the normal temperature range, each thermochromic color memory composition became a color mixture in the color-developed state. The color is visible. In order to put the thermochromic color memory composition into a decolorized state from this state, heating is required, but the heating causes both the thermochromic color memory composition to be decolorized.
Therefore, since one of the initial temperature-sensitive color-memory composition does not return to the anti-counterfeit medium before the color change in the color-developed state, it is possible to confirm whether or not the temperature has been lowered.
The complete decolorization temperature t ₄ of the thermochromic color memory composition in the decolorized state is a temperature equal to or higher than the complete decolorization temperature t _{4 of the} thermochromic color memory composition in the color development state. Therefore, it is easy to exhibit the desired effect. Further, even if the complete decolorization temperature t _{4 of the} thermochromic color memory composition in the decolorized state is less than the complete decolorization temperature t _{4 of the} thermochromic color memory composition in the color development state, the temperature If the difference is 3 ° C. or less, the desired effect can be exhibited.

The temperature indicator is a counterfeiting of an anti-counterfeit medium in which one of the thermochromic color-memory compositions is colored and the other is colorless, the color of the anti-counterfeit medium in which both are colorless, and both in a colored state. The color difference (ΔE ^* _ab ) of the color of the prevention medium is 10 or more, preferably 20 or more, and more preferably 30 or more, respectively.
By having the color difference, it is possible to clearly discriminate the color difference before and after the discoloration, so it is possible to easily confirm whether or not an attempt is made to raise or lower the temperature.

The compounds for the components (a), (b), and (c) of the thermochromic color memory composition are illustrated below.
Examples of the electron-donating color-forming organic compound which is the component (a) of the present invention include diphenylmethanephthalides, phenylindrylphthalides, indolylphthalides, diphenylmethaneazaphthalides, and phenylindolylazaphthalide. Species, fluorans, stirinoquinolins, diazarodamine lactones, pyridines, quinazolines, bisquinazolines and the like.
Examples of these compounds are given below.
3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide,
3- (4-Diethylaminophenyl) -3- (1-ethyl-2-methylindole-3-yl) phthalide,
3,3-bis (1-n-butyl-2-methylindole-3-yl) phthalide,
3,3-Bis (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide,
3- [2-ethoxy-4- (N-ethylanilino) phenyl] -3- (1-ethyl-2-methylindole-3-yl) -4-azaphthalide,
3,6-diphenylaminofluorane,
3,6-dimethoxyfluoran,
3,6-di-n-butoxyfluorane,
2-Methyl-6- (N-ethyl-N-p-trillamino) fluorane,
3-Chloro-6-cyclohexylaminofluorane,
2-Methyl-6-cyclohexylaminofluorane,
2- (2-Chloroamino) -6-dibutylaminofluorane,
2- (2-Chloroanilino) -6-di-n-butylaminofluorane,
2- (3-Trifluoromethylanilino) -6-diethylaminofluorane,
2- (N-Methylanilino) -6- (N-ethyl-N-p-trillamino) fluorane,
1,3-Dimethyl-6-diethylaminofluorane,
2-Chloro-3-methyl-6-diethylaminofluorane,
2-anilino-3-methyl-6-diethylaminofluorane,
2-anilino-3-methoxy-6-diethylaminofluorane,
2-anilino-3-methyl-6-di-n-butylaminofluorane,
2-anilino-3-methoxy-6-di-n-butylaminofluorane,
2-Xylidino-3-methyl-6-diethylaminofluorane,
1,2-Benz-6-diethylaminofluorane,
1,2-Benz-6- (N-ethyl-N-isobutylamino) fluorane,
1,2-Benz-6- (N-ethyl-N-isoamylamino) fluorane,
2- (3-Methoxy-4-dodecoxystilyl) quinoline,
Spiro [5H- (1) benzopyrano (2,3-d) pyrimidine-5,1'(3'H) isobenzofuran] -3'-on,
2- (diethylamino) -8- (diethylamino) -4-methyl-spiro [5H- (1) benzopyrano (2,3-g) pyrimidine-5,1'(3'H) isobenzofuran] -3-one,
2- (Di-n-Butylamino) -8- (Di-n-Butylamino) -4-Methyl-Spiro [5H- (1) Benzopyrano (2,3-g) Pyrimidine-5,1'(3') H) Isobenzofuran] -3-one,
2- (Di-n-butylamino) -8- (diethylamino) -4-methyl-spiro [5H- (1) benzopyrano (2,3-g) pyrimidine-5,1'(3'H) isobenzofuran] -3-on,
2- (Di-n-Butylamino) -8- (N-Ethyl-N-i-Amilamino) -4-Methyl-Spiro [5H- (1) Benzopyrano (2,3-g) Pyrimidine-5,1'(3'H) Isobenzofuran] -3-one,
2- (Dibutylamino) -8- (dipentylamino) -4-methyl-spiro [5H- (1) benzopyrano (2,3-g) pyrimidine-5,1'(3'H) -isobenzofuran] -3 -On,
3- (2-Methoxy-4-dimethylaminophenyl) -3- (1-butyl-2-methylindole-3-yl) -4,5,6,7-tetrachlorophthalide,
3- (2-ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindole-3-yl) -4,5,6,7-tetrachlorophthalide,
3- (2-ethoxy-4-diethylaminophenyl) -3- (1-pentyl-2-methylindole-3-yl) -4,5,6,7-tetrachlorophthalide,
4,5,6,7-Tetrachloro-3- [4- (diethylamino) -2-methylphenyl] -3- (1-ethyl-2-methyl-1H-indole-3-yl) -1 (3H) -Isobenzofuranone,
3', 6'-bis [phenyl (2-methylphenyl) amino] -spiro [isobenzofuran-1 (3H), 9'-[9H] xanthene] -3-one,
3', 6'-bis [phenyl (3-methylphenyl) amino] -spiro [isobenzofuran-1 (3H), 9'-[9H] xanthene] -3-one,
3', 6'-bis [phenyl (3-ethylphenyl) amino] -spiro [isobenzofuran-1 (3H), 9'-[9H] xanthene] -3-one,
4- [2,6-bis (2-ethoxyphenyl) -4-pyridinyl] -N, N-dimethylbenzeneamine,
2- (4'-dimethylaminophenyl) -4-methoxy-quinazoline,
4,4'-(ethylenedioxy) -bis [2- (4-diethylaminophenyl) quinazoline] and the like can be mentioned.
As fluorans, in addition to the above-mentioned compound having a substituent on the phenyl group forming the xanthene ring, a substituent (for example,) on the phenyl group having the substituent on the phenyl group forming the xanthene ring and forming the lactone ring. , An alkyl group such as a methyl group, or a halogen atom such as a chloro group) may be a compound exhibiting a blue color or a black color.

Examples of the electron-accepting compound of the component (b) include a group of compounds having an active proton, a group of pseudo-acidic compounds (a group of compounds that are not acids but act as acids in the composition to develop the color of component (a)). There are compounds having electron vacancies and the like.
Examples of compounds having an active proton include monophenols to polyphenols as compounds having a phenolic hydroxyl group, and alkyl groups, aryl groups, acyl groups, alkoxycarbonyl groups, carboxy groups and esters thereof as their substituents. Alternatively, those having an amide group, a halogen group and the like, bis-type and tris-type phenols and the like, phenol-aldehyde condensed resins and the like can be mentioned. Further, it may be a metal salt of the compound having a phenolic hydroxyl group.
Specific examples are given below.
Phenol, o-cresol, tertiary butyl catechol, nonylphenol, n-octylphenol, n-dodecylphenol, n-stearylphenol, p-chlorophenol, p-bromophenol, o-phenylphenol, n-butyl p-hydroxybenzoate , P-Hydroxybenzoate n-octyl, resorcin, dodecyl gallate, 4,4-dihydroxydiphenylsulfone, bis (4-hydroxyphenyl) sulfide, 1,1-bis (4-hydroxyphenyl) ethane, 1,1- Bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) n-butane, 1,1-bis (4-hydroxyphenyl) n-pentane, 1,1-bis (4-hydroxyphenyl) n-Hexane, 1,1-bis (4-hydroxyphenyl) n-heptane, 1,1-bis (4-hydroxyphenyl) n-octane, 1,1-bis (4-hydroxyphenyl) n-nonane, 1 , 1-bis (4-hydroxyphenyl) n-decane, 1,1-bis (4-hydroxyphenyl) n-dodecane, 1,1-bis (4-hydroxyphenyl) -2-methylpropane, 1,1- Bis (4-hydroxyphenyl) -3-methylbutane, 1,1-bis (4-hydroxyphenyl) -3-methylpentane, 1,1-bis (4-hydroxyphenyl) -2,3-dimethylpentane, 1, 1-bis (4-hydroxyphenyl) -2-ethylbutane, 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 1,1-bis (4-hydroxyphenyl) -3,7-dimethyloctane, 1-Phenyl-1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) n-butane, 2,2-bis (4-Hydroxyphenyl) n-pentane, 2,2-bis (4-hydroxyphenyl) n-hexane, 2,2-bis (4-hydroxyphenyl) n-peptane, 2,2-bis (4-hydroxyphenyl) ) N-octane, 2,2-bis (4-hydroxyphenyl) n-nonane, 2,2-bis (4-hydroxyphenyl) n-decane, 2,2-bis (4-hydroxyphenyl) n-dodecane, 2,2-bis (4-hydroxyphenyl) ethyl propionate, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 2,2-bis (4-hydroxyphenyl) Enyl) -4-methylhexane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 2,2-bis (4-hydroxy-3-methylphenyl) propane and the like.
The compound having a phenolic hydroxyl group can exhibit the most effective thermal discoloration property, but is an aromatic carboxylic acid and an aliphatic carboxylic acid having 2 to 5 carbon atoms, a carboxylic acid metal salt, an acidic phosphoric acid ester and theirs. It may be a compound selected from a metal salt, 1,2,3-triazole and a derivative thereof.

The component (c) of the reaction medium that reversibly causes the electron transfer reaction by the components (a) and (b) in a specific temperature range will be described.
Examples of the component (c) include alcohols, esters, ketones, and ethers.
As the component (c), regarding the color density-temperature curve, a large hysteresis characteristic (a curve plotting a change in coloring density due to a temperature change changes the temperature from the low temperature side to the high temperature side, and a case where the temperature changes from the high temperature side to the low temperature side. A carboxylic acid ester compound having a ΔT value (melting point-cloud point) of 5 ° C. or higher and lower than 50 ° C., which can form a reversible thermochromic composition showing color memory, which changes color depending on the case of changing to , 2-Methylbenzoate stearyl, 4-tert-butylbenzoate cetyl, 4-cyclohexylbenzoate behenyl, 4-phenylbenzoate myristyl, 4-octylbenzoate lauryl, 3,5-dimethylbenzoate hexyl, 3-ethyl Stearyl benzoate, decyl 4-isopropylbenzoate, stearyl 4-benzoyl, phenyl 4-tert-butylbenzoate, 4-chlorobenzyl 2-methylbenzoate, stearyl 4-chlorobenzoate, myristyl 3-bromobenzoate , 2-Chloro-4-bromobenzoate stearyl, 3,4-dichlorobenzoate decyl, 2,4-dibromobenzoate octyl, 3-nitrobenzoate cetyl, 4-aminobenzoate cyclohexylmethyl, 4-diethylaminobenzoic acid Cetyl, stearyl 4-anilinobenzoate, decyl 4-methoxybenzoate, cetyl 4-methoxybenzoate, octyl 4-butoxybenzoate, cetyl 4-hydroxybenzoate, 4-methoxyphenylmethyl benzoate, p-chlorophenylacetic acid Stearyl, p-chlorophenylacetate, benzyl salicylate, neopancil salicylate, 4-methoxymethylphenylmethyl salicylate, 4-chlorophenylmethyl benzoate, 4-chlorophenylmethyl capricate, 4-methoxyphenylmethyl myristate, stearic acid 4-Methylphenylmethyl, 4-nitrophenylmethyl stearate, 4-methylphenylmethyl caproate, 2-chlorophenylmethyl myristate, 4-methoxyphenylmethyl caprate, 4-chlorophenylmethyl 11-bromolaurate , 4-Isopropylphenyl stearate, a carboxylic acid ester containing a substituted aromatic ring in the molecule, stearyl 1-naphthoate, cetyl benzylate, stearyl benzylate, decyl 3-benzoylpropionate, stearyl benzoate, benzoic acid Esters of carboxylic acids containing unsubstituted aromatic rings such as cetyl and myristyl benzoate and aliphatic alcohols having 10 or more carbon atoms, cyclohea silicate In molecules such as xylmethyl, cyclohexyl laurate, cyclohexyl myristate, cyclohexyl palmitate, cyclohexyl stearate, cyclohexyl stearate, stearyl cyclohexylacetate, stearyl 2-cyclohexylpropionate, stearyl cyclohexanecarboxylic acid, cyclohexyl 2-benzoylpropionate, etc. Fatty acids with 6 or more carbon atoms such as carboxylic acid esters containing cyclohexyl groups, benzyl caproate, benzyl palmitate, 4-methylbenzyl palmitate, 3-phenylpropyl stearate, phenyl 11-bromolaurate, and aromatic alcohols. Alternatively, an ester of a phenol, an ester of a fatty acid having 8 or more carbon atoms such as neopentyl octylate and neopentyl laurate and an ester of a branched aliphatic alcohol, a dicarboxylic acid such as dibenzyl sebacate, dineopentyl 4,4'-diphenyldicarboxylic acid, and dibenzyl azodicarboxylate. Esters of acids and aromatic alcohols or branched aliphatic alcohols, dibenzyl silicate, heptyl stearate, didecyl adipate, dilauryl adipate, dimyristyl adipate, disetyl adipate, distearyl adipate, trilaurin, trimyristin, tristearate , Dimyristin, distearate and the like are used.

Further, an odd aliphatic monohydric alcohol having 9 or more carbon atoms and a fatty acid ester compound obtained from an aliphatic carboxylic acid having an even number of carbon atoms, n-pentyl alcohol or n-heptyl alcohol and an even fat having 10 to 16 carbon atoms. Aliphatic ester compounds having a total carbon number of 17 to 23 obtained from group carboxylic acids are also effective.
Specifically, n-pentadecyl acetate, n-tridecyl butyrate, n-pentadecyl butyrate, n-undecyl caproate, n-tridecyl caproate, n-pentadecyl caproate, n-nonyl caprylate, n-undecyl caprylate, N-tridecyl caprylate, n-pentadecyl caprylate, n-heptyl caprate, n-nonyl caprate, n-undecyl caprate, n-tridecyl caprate, n-pentadecyl caprate, n-pentyl laurate, laurate n-heptyl, n-nonyl laurate, n-undecyl laurate, n-tridecyl laurate, n-pentadecyl laurate, n-pentyl myristate, n-heptyl myristate, n-nonyl myristate, n-myristate Undecyl, n-tridecyl myristate, n-pentadecyl myristate, n-pentyl palmitate, n-heptyl palmitate, n-nonyl palmitate, n-undecyl palmitate, n-tridecyl palmitate, n-pentadecyl palmitate, N-nonyl stearate, n-undecyl stearate, n-tridecyl stearate, n-pentadecyl stearate, n-nonyl eikosanate, n-undecyl eikosanate, n-tridecyl eikosanate, n-pentadecyl eikosanate, behenic acid Examples thereof include n-nonyl, n-undecyl behenate, n-tridecyl behenate, and n-pentadecyl behenate.

As the ketones, aliphatic ketones having a total carbon number of 10 or more are effective, and 2-decanone, 3-decanone, 4-decanone, 2-undecanone, 3-undecanone, 4-undecanone, and 5-undecanone are effective. , 2-Dodecanone, 3-Dodecanone, 4-Dodecanone, 5-Dodecanone, 2-Tridecanone, 3-Tridecanone, 2-Tetradecanone, 2-Pentadecanone, 8-Pentadecanone, 2-Hexadecanone, 3-Hexadecanone, 9-Heptadecanone, 2 -Pentadecanone, 2-octadecanone, 2-nonadecanone, 10-nonadecanone, 2-eicosanone, 11-eicosanone, 2-heneicosanone, 2-docosanone, lauron, stearone and the like can be mentioned.
Also, arylalkyl ketones having a total carbon number of 12 to 24, for example, n-octadecanophenone, n-heptadecanophenone, n-hexadecanophenone, n-pentadecanophenone, n-tetradecano. Phenone, 4-n-dodecaacetophenone, n-tridecanophenone, 4-n-undecanoacetophenone, n-laurofenone, 4-n-decanoacetophenone, n-undecanophenone, 4-n-nonylacetophenone, n -Decanofenone, 4-n-octylacetophenone, n-nonanophenone, 4-n-heptylacetophenone, n-octanophenone, 4-n-hexylacetophenone, 4-n-cyclohexylacetophenone, 4-tert-butylpropiophenone, n-Heptaphenone, 4-n-pentylacetophenone, cyclohexylphenylketone, benzyl-n-butylketone, 4-n-butylacetophenone, n-hexanophenone, 4-isobutylacetophenone, 1-acetonaphthone, 2-acetonafton, cyclopentylphenylketone And so on.

As the ethers, aliphatic ethers having a total carbon number of 10 or more are effective, and dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, dinonyl ether, didecyl ether, diundecyl ether, and didodecyl ether. , Ditridecyl ether, ditetradecyl ether, dipentadecyl ether, dihexadecyl ether, dioctadecyl ether, decanediol dimethyl ether, undecanediol dimethyl ether, dodecanediol dimethyl ether, tridecanediol dimethyl ether, decanediol diethyl ether, undecanediol diethyl ether Etc. can be mentioned.

〔式中、Ｒ_１は水素原子又はメチル基を示し、ｍは０〜２の整数を示し、Ｘ_１、Ｘ_２のいずれか一方は−（ＣＨ_２）_ｎＯＣＯＲ_２又は−（ＣＨ_２）_ｎＣＯＯＲ_２、他方は水素原子を示し、ｎは０〜２の整数を示し、Ｒ_２は炭素数４以上のアルキル基又はアルケニル基を示し、Ｙ_１及びＹ_２は水素原子、炭素数１〜４のアルキル基、メトキシ基、又は、ハロゲンを示し、ｒ及びｐは１〜３の整数を示す。〕
前記式（１）で示される化合物のうち、Ｒ_１が水素原子の場合、より広いヒステリシス幅を有する可逆熱変色性組成物が得られるため好適であり、更にＲ_１が水素原子であり、且つ、ｍが０の場合がより好適である。
なお、式（１）で示される化合物のうち、より好ましくは下記一般式（２）で示される化合物が用いられる。

式中のＲは炭素数８以上のアルキル基又はアルケニル基を示すが、好ましくは炭素数１０〜２４のアルキル基、更に好ましくは炭素数１２〜２２のアルキル基である。
前記化合物として具体的には、オクタン酸−４−ベンジルオキシフェニルエチル、ノナン酸−４−ベンジルオキシフェニルエチル、デカン酸−４−ベンジルオキシフェニルエチル、ウンデカン酸−４−ベンジルオキシフェニルエチル、ドデカン酸−４−ベンジルオキシフェニルエチル、トリデカン酸−４−ベンジルオキシフェニルエチル、テトラデカン酸−４−ベンジルオキシフェニルエチル、ペンタデカン酸−４−ベンジルオキシフェニルエチル、ヘキサデカン酸−４−ベンジルオキシフェニルエチル、ヘプタデカン酸−４−ベンジルオキシフェニルエチル、オクタデカン酸−４−ベンジルオキシフェニルエチルを例示できる。 Further, as the component (c), a compound represented by the following general formula (1) can also be used.

[In the formula, R ₁ represents a hydrogen atom or a methyl group, m represents an integer of 0 to ₂ , and either X ₁ or X ₂ is − (CH ₂ ) _n OCOR ₂ or − (CH ₂ ) _n. COOR ₂ , the other represents a hydrogen atom, n represents an integer of 0 to 2, R ₂ represents an alkyl or alkenyl group having 4 or more carbon atoms, Y ₁ and Y ₂ represent a hydrogen atom and 1 to 4 carbon atoms. Indicates an alkyl group, a methoxy group, or a halogen, and r and p represent integers of 1 to 3. ]
Among the compounds represented by the formula (1), when R ₁ is a hydrogen atom, it is suitable because a reversible thermochromic composition having a wider hysteresis width can be obtained, and further, R ₁ is a hydrogen atom and , M is more preferably 0.
Of the compounds represented by the formula (1), the compound represented by the following general formula (2) is more preferably used.

R in the formula represents an alkyl group or an alkenyl group having 8 or more carbon atoms, preferably an alkyl group having 10 to 24 carbon atoms, and more preferably an alkyl group having 12 to 22 carbon atoms.
Specifically, the compounds include -4-benzyloxyphenylethyl octanoate, -4-benzyloxyphenylethyl nonanoate, -4-benzyloxyphenylethyl decanoate, -4-benzyloxyphenylethyl undecanoate, and dodecanoic acid. -4-benzyloxyphenylethyl, 4-benzyloxyphenylethyl tridecanoate, -4-benzyloxyphenylethyl tetradecanoate, -4-benzyloxyphenylethyl pentadecanoic acid, -4-benzyloxyphenylethyl hexadecanoic acid, heptadecanoic acid Examples thereof include -4-benzyloxyphenylethyl and -4-benzyloxyphenylethyl octadecanoic acid.

（式中、Ｒは炭素数８以上のアルキル基又はアルケニル基を示し、ｍ及びｎはそれぞれ１〜３の整数を示し、Ｘ及びＹはそれぞれ水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、ハロゲンを示す。）
前記化合物として具体的には、オクタン酸１,１−ジフェニルメチル、ノナン酸１,１−ジフェニルメチル、デカン酸１,１−ジフェニルメチル、ウンデカン酸１,１−ジフェニルメチル、ドデカン酸１,１−ジフェニルメチル、トリデカン酸１,１−ジフェニルメチル、テトラデカン酸１,１−ジフェニルメチル、ペンタデカン酸１,１−ジフェニルメチル、ヘキサデカン酸１,１−ジフェニルメチル、ヘプタデカン酸１,１−ジフェニルメチル、オクタデカン酸１,１−ジフェニルメチルを例示できる。 Further, as the component (c), a compound represented by the following general formula (3) can also be used.

(In the formula, R represents an alkyl group or an alkoxy group having 8 or more carbon atoms, m and n represent integers of 1 to 3 respectively, and X and Y represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and carbon, respectively. Indicates the number 1 to 4 alkoxy groups and halogens.)
Specifically, the compounds include octanoic acid 1,1-diphenylmethyl, nonanoic acid 1,1-diphenylmethyl, decanoic acid 1,1-diphenylmethyl, undecanoic acid 1,1-diphenylmethyl, and dodecanoic acid 1,1-. Diphenylmethyl, tridecanoic acid 1,1-diphenylmethyl, tetradecanoic acid 1,1-diphenylmethyl, pentadecaneic acid 1,1-diphenylmethyl, hexadecanoic acid 1,1-diphenylmethyl, heptadecanoic acid 1,1-diphenylmethyl, octadecanoic acid 1,1-Diphenylmethyl can be exemplified.

（式中、Ｘは水素原子、炭素数１乃至４のアルキル基、メトキシ基、ハロゲン原子のいずれかを示し、ｍは１乃至３の整数を示し、ｎは１乃至２０の整数を示す。）
前記化合物としては、マロン酸と２−〔４−(４−クロロベンジルオキシ）フェニル）〕エタノールとのジエステル、こはく酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、こはく酸と２−〔４−(３−メチルベンジルオキシ）フェニル）〕エタノールとのジエステル、グルタル酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、グルタル酸と２−〔４−(４−クロロベンジルオキシ）フェニル）〕エタノールとのジエステル、アジピン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、ピメリン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、スベリン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、スベリン酸と２−〔４−(３−メチルベンジルオキシ）フェニル）〕エタノールとのジエステル、スベリン酸と２−〔４−(４−クロロベンジルオキシ）フェニル）〕エタノールとのジエステル、スベリン酸と２−〔４−(２，４−ジクロロベンジルオキシ）フェニル）〕エタノールとのジエステル、アゼライン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、セバシン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、１，１０−デカンジカルボン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、１，１８-オクタデカンジカルボン酸と２−（４−ベンジルオキシフェニル）エタノールとのジエステル、１，１８-オクタデカンジカルボン酸と２−〔４−(２−メチルベンジルオキシ）フェニル）〕エタノールとのジエステルを例示できる。 Further, as the component (c), a compound represented by the following general formula (4) can also be used.

(In the formula, X represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a methoxy group, or a halogen atom, m represents an integer of 1 to 3, and n represents an integer of 1 to 20.)
Examples of the compound include a diester of malonic acid and 2- [4- (4-chlorobenzyloxy) phenyl)] ethanol, a diester of oxalic acid and 2- (4-benzyloxyphenyl) ethanol, and a diester of oxalic acid and 2-. [4- (3-Methylbenzyloxy) phenyl)] Diester with ethanol, Diester with glutaric acid and 2- (4-benzyloxyphenyl) ethanol, Diester with glutaric acid and 2- [4- (4-chlorobenzyloxy) Phenyl)] Diester with ethanol, diester with adipic acid and 2- (4-benzyloxyphenyl) ethanol, diester with pimeric acid and 2- (4-benzyloxyphenyl) ethanol, suberic acid and 2- (4-benzyloxyphenyl) ethanol Diester with benzyloxyphenyl) ethanol, diester with suberic acid and 2- [4- (3-methylbenzyloxy) phenyl)] Diester with ethanol, diester with suberic acid and 2- [4- (4-chlorobenzyloxy) phenyl)] Diester with ethanol, diester with suberic acid and 2- [4- (2,4-dichlorobenzyloxy) phenyl)] ethanol, diester with azelaic acid and 2- (4-benzyloxyphenyl) ethanol, with sebacic acid Diester with 2- (4-benzyloxyphenyl) ethanol, diester with 1,10-decandicarboxylic acid and 2- (4-benzyloxyphenyl) ethanol, 1,18-octadecanedicarboxylic acid and 2- (4-benzyl) Examples thereof include a diester with oxyphenyl) ethanol, and a diester with 1,18-octadecanedicarboxylic acid and 2- [4- (2-methylbenzyloxy) phenyl)] ethanol.

（式中、Ｒは炭素数１乃至２１のアルキル基又はアルケニル基を示し、ｎは１乃至３の整数を示す。）
前記化合物としては、１，３−ビス（２−ヒドロキシエトキシ）ベンゼンとカプリン酸とのジエステル、１，３−ビス（２−ヒドロキシエトキシ）ベンゼンとウンデカン酸とのジエステル、１，３−ビス（２−ヒドロキシエトキシ）ベンゼンとラウリン酸とのジエステル、１，３−ビス（２−ヒドロキシエトキシ）ベンゼンとミリスチン酸とのジエステル、１，４−ビス（ヒドロキシメトキシ）ベンゼンと酪酸とのジエステル、１，４−ビス（ヒドロキシメトキシ）ベンゼンとイソ吉草酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンと酢酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとプロピオン酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンと吉草酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとカプロン酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとカプリル酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとカプリン酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとラウリン酸とのジエステル、１，４−ビス（２−ヒドロキシエトキシ）ベンゼンとミリスチン酸とのジエステルを例示できる。 Further, as the component (c), a compound represented by the following general formula (5) can also be used.

(In the formula, R represents an alkyl group or an alkenyl group having 1 to 21 carbon atoms, and n represents an integer of 1 to 3).
Examples of the compound include a diester of 1,3-bis (2-hydroxyethoxy) benzene and capric acid, a diester of 1,3-bis (2-hydroxyethoxy) benzene and undecanoic acid, and 1,3-bis (2). Diester of -hydroxyethoxy) benzene and lauric acid, diester of 1,3-bis (2-hydroxyethoxy) benzene and myristic acid, diester of 1,4-bis (hydroxymethoxy) benzene and butyric acid, 1,4 -Diester of bis (hydroxymethoxy) benzene and isovaleric acid, diester of 1,4-bis (2-hydroxyethoxy) benzene and acetic acid, 1,4-bis (2-hydroxyethoxy) benzene and propionic acid Diester, diester of 1,4-bis (2-hydroxyethoxy) benzene and valerate, diester of 1,4-bis (2-hydroxyethoxy) benzene and caproic acid, 1,4-bis (2-hydroxyethoxy) ) Diester of benzene and capric acid, diester of 1,4-bis (2-hydroxyethoxy) benzene and capric acid, diester of 1,4-bis (2-hydroxyethoxy) benzene and lauric acid, 1,4 An example is an example of a diester of −bis (2-hydroxyethoxy) benzene and myristic acid.

（式中、Ｘは水素原子、炭素数１乃至４のアルキル基、炭素数１乃至４のアルコキシ基、ハロゲン原子のいずれかを示し、ｍは１乃至３の整数を示し、ｎは１乃至２０の整数を示す。）
前記化合物としては、こはく酸と２−フェノキシエタノールとのジエステル、スベリン酸と２−フェノキシエタノールとのジエステル、セバシン酸と２−フェノキシエタノールとのジエステル、１，１０-デカンジカルボン酸と２−フェノキシエタノールとのジエステル、１，１８-オクタデカンジカルボン酸と２−フェノキシエタノールとのジエステルを例示できる。 Further, as the component (c), a compound represented by the following general formula (6) can also be used.

(In the formula, X represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, m represents an integer of 1 to 3, and n represents 1 to 20. Indicates an integer of.)
Examples of the compound include a diester of succinic acid and 2-phenoxyethanol, a diester of suberic acid and 2-phenoxyethanol, a diester of sebacic acid and 2-phenoxyethanol, and a diester of 1,10-decandicarboxylic acid and 2-phenoxyethanol. Examples thereof include a diester of 1,18-octadecanedicarboxylic acid and 2-phenoxyethanol.

（式中、Ｒは炭素数４乃至２２のアルキル基、シクロアルキルアルキル基、シクロアルキル基、炭素数４乃至２２のアルケニル基のいずれかを示し、Ｘは水素原子、炭素数１乃至４のアルキル基、炭素数１乃至４のアルコキシ基、ハロゲン原子のいずれかを示し、ｎは０又は１を示す。）
前記化合物としては、４−フェニル安息香酸デシル、４−フェニル安息香酸ラウリル、４−フェニル安息香酸ミリスチル、４−フェニル安息香酸シクロヘキシルエチル、４−ビフェニル酢酸オクチル、４−ビフェニル酢酸ノニル、４−ビフェニル酢酸デシル、４−ビフェニル酢酸ラウリル、４−ビフェニル酢酸ミリスチル、４−ビフェニル酢酸トリデシル、４−ビフェニル酢酸ペンタデシル、４−ビフェニル酢酸セチル、４−ビフェニル酢酸シクロペンチル、４−ビフェニル酢酸シクロヘキシルメチル、４−ビフェニル酢酸ヘキシル、４−ビフェニル酢酸シクロヘキシルメチルを例示できる。 Further, as the component (c), a compound represented by the following general formula (7) can also be used.

(In the formula, R represents any of an alkyl group having 4 to 22 carbon atoms, a cycloalkyl alkyl group, a cycloalkyl group, and an alkoxy group having 4 to 22 carbon atoms, and X is a hydrogen atom and an alkyl having 1 to 4 carbon atoms. Indicates a group, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, and n indicates 0 or 1).
Examples of the compound include decyl 4-phenylbenzoate, lauryl 4-phenylbenzoate, myristyl 4-phenylbenzoate, cyclohexylethyl 4-phenylbenzoate, octyl 4-biphenylacetate, nonyl 4-biphenylacetate, and 4-biphenylacetic acid. Decyl, 4-biphenylacetate lauryl, 4-biphenylacetate myristyl, 4-biphenylacetate tridecyl, 4-biphenylacetate pentadecyl, 4-biphenylacetate cetyl, 4-biphenylacetate cyclopentyl, 4-biphenylacetate cyclohexylmethyl, 4-biphenylacetate hexyl , 4-Cyclohexylmethyl biphenylacetate can be exemplified.

（式中、Ｒは炭素数３乃至１８のアルキル基、炭素数３乃至１８の脂肪族アシル基のいずれかを示し、Ｘは水素原子、炭素数１乃至３のアルキル基、炭素数１又は２のアルコキシ基、ハロゲン原子のいずれかを示し、Ｙは水素原子、メチル基のいずれかを示し、Ｚは水素原子、炭素数１乃至４のアルキル基、炭素数１又は２のアルコキシ基、ハロゲン原子のいずれかを示す。）
前記化合物としては、４−ブトキシ安息香酸フェノキシエチル、４−ペンチルオキシ安息香酸フェノキシエチル、４−テトラデシルオキシ安息香酸フェノキシエチル、４−ヒドロキシ安息香酸フェノキシエチルとドデカン酸とのエステル、バニリン酸フェノキシエチルのドデシルエーテルを例示できる。 Further, as the component (c), a compound represented by the following general formula (8) can also be used.

(In the formula, R represents any of an alkyl group having 3 to 18 carbon atoms and an aliphatic acyl group having 3 to 18 carbon atoms, and X is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, and 1 or 2 carbon atoms. Indicates either an alkoxy group or a halogen atom, Y indicates either a hydrogen atom or a methyl group, Z is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 or 2 carbon atoms, or a halogen atom. Indicates one of.)
Examples of the compound include phenoxyethyl 4-butoxybenzoate, phenoxyethyl 4-pentyloxybenzoate, phenoxyethyl 4-tetradecyloxybenzoate, an ester of phenoxyethyl 4-hydroxybenzoate and dodecanoic acid, and phenoxyethyl vanillate. Dodecyl ether can be exemplified.

（式中、Ｒは炭素数４乃至２２のアルキル基、炭素数４乃至２２のアルケニル基、シクロアルキルアルキル基、シクロアルキル基のいずれかを示し、Ｘは水素原子、アルキル基、アルコキシ基、ハロゲン原子のいずれかを示し、Ｙは水素原子、アルキル基、アルコキシ基、ハロゲン原子のいずれかを示し、ｎは０又は１を示す。）
前記化合物としては、ｐ−ヒドロキシ安息香酸オクチルの安息香酸エステル、ｐ−ヒドロキシ安息香酸デシルの安息香酸エステル、ｐ−ヒドロキシ安息香酸ヘプチルのｐ−メトキシ安息香酸エステル、ｐ−ヒドロキシ安息香酸ドデシルのo-メトキシ安息香酸エステル、ｐ−ヒドロキシ安息香酸シクロヘキシルメチルの安息香酸エステルを例示できる。 Further, as the component (c), a compound represented by the following general formula (9) can also be used.

(In the formula, R represents any of an alkyl group having 4 to 22 carbon atoms, an alkenyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group, and a cycloalkyl group, and X is a hydrogen atom, an alkyl group, an alkoxy group, and a halogen. Indicates any of the atoms, Y indicates any of a hydrogen atom, an alkyl group, an alkoxy group, and a halogen atom, and n indicates 0 or 1).
Examples of the compound include benzoic acid ester of octyl p-hydroxybenzoate, benzoic acid ester of decyl p-hydroxybenzoate, p-methoxybenzoic acid ester of heptyl p-hydroxybenzoate, and o-decyl of dodecyl p-hydroxybenzoate. Examples thereof include methoxybenzoic acid ester and benzoic acid ester of cyclomethylmethyl p-hydroxybenzoate.

The blending ratios of the components (a), (b), and (c) depend on the concentration, discoloration temperature, discoloration form, and type of each component, but in general, the component ratio at which the desired discoloration characteristics can be obtained is determined. The range of (b) component 0.1 to 50, preferably 0.5 to 20, and (c) component 1 to 800, preferably 5 to 200 with respect to (a) component 1 (all of the above ratios). It is a mass part). Further, each component may be used as a mixture of two or more kinds.

The thermochromic color memory composition is encapsulated in a microcapsule wall film and used as a reversible thermochromic microcapsule pigment. This is because the thermochromic color memory composition can be kept in the same composition under various usage conditions and can exert the same action and effect.
Examples of the method for microencapsulating the thermochromic color memory composition include an interfacial polymerization method, an interfacial polycondensation method, an in-Situ polymerization method, an in-liquid curing coating method, a phase separation method from an aqueous solution, and an organic solvent. There are a phase separation method, a melt dispersion cooling method, an air suspension coating method, a spray drying method, and the like, which are appropriately selected according to the application. Further, a secondary resin film may be provided on the surface of the microcapsules according to the purpose to impart durability, or the surface characteristics may be modified for practical use.
Here, the mass ratio of the thermochromic color memory composition to the microcapsule wall film satisfies the range of 7: 1 to 1: 1, preferably 6: 1 to 1: 1.
When the ratio of the thermochromic color memory composition to the wall film is larger than the above range, the thickness of the wall film becomes too thin and the resistance to pressure and heat tends to decrease, and the thermochromic color of the wall film tends to decrease. When the ratio to the memory composition is larger than the above range, the color density and sharpness at the time of color development are likely to decrease.

When the reversible thermochromic layer also serves as a support, it can be obtained by blending a thermochromic color memory composition with a molding resin selected from a thermoplastic resin and a thermosetting resin and molding the composition.
Examples of the molding resin include linear low-density polyethylene, low-density polyethylene, medium-high-density polyethylene, ultra-high-density polyethylene, chlorinated polyethylene, polypropylene, chlorinated polypropylene, poloisobutylene, polybutadiene, polymethylpentene, polystyrene, and polyethylene terephthalate. , Polybutylene terephthalate, polyvinyl acetate, vinyl chloride resin, chlorinated polyvinyl chloride, polyvinylidene chloride, acrylic acid ester resin, methacrylic acid ester resin, polyamide, copolymerized polyamide, polyamideimide, polyacetal, polyvinylformal, polyvinylbutyral, Polyarylate, polyetherimide, polyether ether ketone, polycarbonate, polyphenyl ether, polyphenylene sulfide, polysulfone, fluororesin, ionomer resin, ethylene-propylene copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-vinyl alcohol copolymer Resin, ethylene-acrylic acid ester copolymer resin, ethylene-methacrylic acid ester copolymer resin, ethylene-vinyl chloride copolymer resin, vinyl chloride-propylene copolymer resin, vinyl chloride-vinylidene chloride copolymer resin, styrene-butadiene copolymer Resin, acrylonitrile-vinylidene chloride copolymer resin, acrylonitrile-styrene copolymer resin, acrylonitrile-ethylene-styrene copolymer resin, acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile-chlorinated polyethylene-styrene copolymer resin, acrylonitrile-acrylic acid Ester-styrene copolymer resin, ethylene-vinyl acetate resin-vinyl chloride graft copolymer resin, methyl methacrylate-butadiene-styrene copolymer resin, styrene-based thermoplastic elastomer, olefin-based plastic elastomer, urethane-based plastic elastomer, polyester-based plasticity Elastomer, 1,2-polybutadiene plastic elastomer, vinyl chloride plastic elastomer, petroleum hydrocarbon resin, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, nitrocellulose, low molecular weight polyethylene, low molecular weight polypropylene, polybutene, Kumaron-inden copolymer, thermoplastic resin such as phenoxyplastic, epoxy resin, xylene resin, toluene resin, guanamine resin, epoxy acrylate, phenol resin, unsaturated polyester tree Examples thereof include thermosetting resins such as fat, furan resin, polyimide, poly (p-hydroxybenzoic acid), polyurethane, urea resin, melamine resin, and silicone resin.

If the support is provided, screen printing, offset printing, gravure printing, and coater are used on the support using inks and paints dispersed in a vehicle containing a thermochromic color memory composition and a binder resin. , A reversible thermal discoloration layer is provided by a printing method such as transfer printing or a coating method such as spray coating.
As the support, cloth such as paper, synthetic paper, knitted cloth, woven cloth, non-woven fabric, synthetic leather, leather, plastic, glass, ceramics, metal, wood, stone and the like are used. Further, the form is preferably flat, but may be uneven.

The binder resin may be either a water-soluble resin or an oil-soluble resin, and can be appropriately selected and used depending on the intended purpose.
Specifically, general-purpose resins such as ionomer resin, isobutylene-maleic anhydride resin copolymer resin, acrylonitrile-acrylic styrene copolymer resin, acrylonitrile-styrene copolymer resin, acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile Chlorinated polyethylene-styrene copolymer resin, ethylene-vinyl chloride copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate-vinyl chloride graft copolymer resin, vinylidene chloride resin, vinyl chloride resin, chlorinated vinyl chloride resin , Vinyl chloride-vinylidene chloride copolymer resin, chlorinated polyethylene resin, chlorinated polypropylene resin, polyamide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polycarbonate resin, polystyrene resin, high impact polystyrene resin, polypropylene resin, polymethylstyrene resin , Polyacrylic acid ester resin, polymethylmethacrylate resin, epoxy acrylate resin, alkylphenol resin, rosin-modified alkyd resin, rosin-modified alkyd resin, phenol resin-modified alkyd resin, epoxy resin-modified alkyd resin, styrene-modified alkyd resin, acrylic-modified alkyd resin. , Aminoalkyd resin, vinyl chloride-vinyl acetate resin, styrene-butadiene resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyurethane resin, alkyd resin, natural rubber, polyisobutylene, butyl rubber, polyvinyl alkyl ether, rosin, rosin Esters, rosin derivatives, polyterpene resins, oil-soluble phenolic resins, petroleum hydrocarbon resins, shellacs, cyclized rubber, vinyl acetate emulsion resins, styrene-butadiene emulsion resins, alkyd ester emulsion resins, aqueous silicon rubber emulsion resins , Water-soluble alkyd resin, water-soluble melamine resin, water-soluble urea resin, water-soluble phenol resin, water-soluble epoxy resin, water-soluble polybutadiene resin, cellulose acetate, cellulose nitrate, ethyl cellulose and the like.
Further, the resin may be used alone or in combination of two or more.

A transparent protective layer may be provided on the reversible thermal discoloration layer to impart scratch resistance, or a light stabilizer layer may be provided.
Specifically, the light stabilizer layer is selected from an ultraviolet absorber, an antioxidant, an antioxidant, a single-term oxygen quencher, a superoxide anion quencher, an ozone quencher, a visible light absorber, and an infrared absorber. This is a layer in which the light stabilizer is fixed in a dispersed state.

The temperature indicator can also be used as a counterfeit detection material, and can also be used as an indicator for detecting a supercooled state or an overheated state of foods.

Examples are shown below, but the present invention is not limited to the examples. In addition, the part in an Example shows a mass part.
Example 1
Preparation of Reversible Thermochromic Microcapsule Pigment A (a) 4,5,6,7-Tetrachloro-3- [4- (diethylamino) -2-methylphenyl] -3- (1-ethyl-2-) as a component Methyl-1H-indol-3-yl) -1 (3H) -isocyanbenzofuranone 2.0 parts, 4,4'-(2-ethylhexane-1,1-diyl) diphenol as (b) component 3. Thermochromic color memory consisting of 0 parts, 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane 5.0 parts, and (c) component 4-benzyloxyphenylethyl capricate 50.0 parts. The composition was heated and dissolved, and a solution obtained by mixing 30.0 parts of an aromatic isocyanate prepolymer and 40.0 parts of an auxiliary solvent as a wall film material was emulsified and dispersed in an 8% polyvinyl alcohol aqueous solution, and stirred while heating. After that, 2.5 parts of water-soluble aliphatic modified amine was added, and further stirring was continued to obtain a microcapsule suspension. The suspension was centrifuged to isolate a reversible thermal discoloration microcapsule pigment.
The average particle size of the microcapsule pigment is 2.2 μm, and the behavior has hysteresis characteristics of t1: −20 ° C., t2: −10 ° C., t3: 46 ° C., t4: 56 ° C., ΔH: 66 ° C. The color changed reversibly from blue to colorless and from colorless to blue.

Preparation of Reversible Thermochromic Microcapsule Pigment B (a) 2- (dibutylamino) -8- (dipentylamino) -4-methyl-spiro [5H- [1] benzopyrano [2,3-g] pyrimidin- as a component 5,1'(3'H) -isocyanbenzofuran] -3-one 1.0 part, (b) component 4,4'-(2-ethylhexane-1,1-diyl) diphenol 3.0 part , 2,2-Bis (4'-hydroxyphenyl) -hexafluoropropane 5.0 parts, (c) Temperature-sensitive discoloration color memory composition consisting of 50.0 parts of capricate-4-benzyloxyphenylethyl as a component A solution obtained by heating and dissolving a substance and mixing 30.0 parts of an aromatic isocyanate prepolymer and 40.0 parts of an auxiliary solvent as a wall film material was emulsified and dispersed in an 8% aqueous solution of polyvinyl alcohol, and stirred while heating. After that, 2.5 parts of water-soluble aliphatic modified amine was added, and further stirring was continued to obtain a microcapsule suspension. The suspension was centrifuged to isolate a reversible thermal discoloration microcapsule pigment.
The average particle size of the microcapsule pigment is 2.3 μm, and the hysteresis characteristics are t ₁ : -20 ° C, t ₂ : -10 ° C, t ₃ : 48 ° C, t ₄ : 58 ° C, ΔH: 68 ° C. The color changed reversibly from pink to colorless and from colorless to pink.

Preparation of anti-counterfeit medium (see Fig. 2)
As the support 3, 15 parts of reversible thermochromic microcapsule pigment A, which was previously cooled to -20 ° C or lower to make it blue, 15 parts of reversible thermochromic microcapsule pigment B in a colorless state, and urethane-based emulsion resin 62 on white synthetic paper. Solid printing of reversible thermochromic ink, which is made by uniformly dispersing parts, 2 parts of thickener, 0.5 parts of leveling agent, 0.5 parts of defoaming agent, and 5 parts of cross-linking agent, using a 120-mesh screen plate. Was dried and cured to form a reversible thermal discoloration layer 2 to obtain an anti-counterfeit medium 1.
At room temperature (25 ° C.), the anti-counterfeit medium has a blue color due to the reversible thermochromic microcapsule pigment A, and the state is maintained in the room temperature range.
Next, when the anti-counterfeit medium was heated to 58 ° C. or higher, the reversible thermochromic microcapsule pigment A was decolorized and became colorless, and the white color of the support was visually recognized.
When the white anti-counterfeit medium is cooled to −20 ° C. or lower, the reversible thermochromic microcapsule pigment A and the reversible thermochromic microcapsule pigment B are both colored to prevent purple, which is a mixture of blue and pink. The medium was visible.
When heated again and reaches a temperature of 56 ° C or higher, only the reversible thermochromic microcapsule pigment A is decolorized and becomes pink, and when the temperature is 58 ° C or higher, the reversible thermochromic microcapsule pigment B is decolorized and colorless. It was not possible to return to the initial blue anti-counterfeit medium, and it had a function as an anti-counterfeit medium.
The color difference ΔE ^* _ab between the blue anti-counterfeit medium and the white anti-counterfeit medium was 64.9 when measured using a fluorescence spectrophotometer manufactured by Konica Minolta, product number: FD-7, and the blue anti-counterfeit medium and purple. The color difference ΔE ^* _ab of the anti-counterfeit medium was 67.3.
Further, the anti-counterfeit medium also has a function as a temperature indicator for detecting that the temperature exceeds a predetermined temperature or a temperature indicator for detecting that the temperature has fallen below the predetermined temperature.

Example 2
Preparation of anti-counterfeit medium (see Fig. 3)
15 parts of reversible thermochromic microcapsule pigment A, 77 parts of urethane emulsion resin, 2 parts of thickener, 0.5 part of leveling agent, which was previously cooled to -20 ° C or lower to turn blue on white synthetic paper as the support 3. , 0.5 part of defoaming agent and 5 parts of cross-linking agent are uniformly dispersed, and solid printing is performed using a 120-mesh screen plate, and the mixture is dried and cured to provide a reversible heat-discoloring layer A21. It was.
Next, on the reversible heat-discoloring layer A, 15 parts of the colorless reversible heat-discoloring microcapsule pigment B, 77 parts of the urethane emulsion resin, 2 parts of the thickener, 0.5 part of the leveling agent, and 0 parts of the defoaming agent. A reversible thermochromic ink obtained by uniformly dispersing 5 parts and 5 parts of a cross-linking agent is solid-printed using a 120-mesh screen plate and dried and cured to form a reversible thermochromic layer B22 to form an anti-counterfeit medium 1. Got
At room temperature (25 ° C.), the anti-counterfeit medium has a blue color due to the reversible thermochromic microcapsule pigment A, and the state is maintained in the room temperature range.
Next, when the anti-counterfeit medium was heated to 58 ° C. or higher, the reversible thermochromic microcapsule pigment A was decolorized and became colorless, and the white color of the support was visually recognized.
When the white anti-counterfeit medium is cooled to −20 ° C. or lower, the reversible thermochromic microcapsule pigment A and the reversible thermochromic microcapsule pigment B are both colored to prevent purple, which is a mixture of blue and pink. The medium was visible.
When heated again and reaches a temperature of 56 ° C or higher, only the reversible thermochromic microcapsule pigment A is decolorized and becomes pink, and when the temperature is 58 ° C or higher, the reversible thermochromic microcapsule pigment B is decolorized and colorless. It was not possible to return to the initial blue anti-counterfeit medium, and it had a function as an anti-counterfeit medium.
The color difference ΔE ^* _ab between the blue anti-counterfeit medium and the white anti-counterfeit medium was 69.3 when measured using a Konica Minolta fluorescence spectrophotometer, product number: FD-7, and the blue anti-counterfeit medium and purple. The color difference of the anti-counterfeit medium was 64.5.
Further, the anti-counterfeit medium also has a function as a temperature indicator for detecting that the temperature exceeds a predetermined temperature or a temperature indicator for detecting that the temperature has fallen below the predetermined temperature.

Example 3
Preparation of anti-counterfeit medium (see Fig. 4)
Reversible thermochromic microcapsule pigment B in a colorless state, 1 part of dispersant, 79 parts of polypropylene homopolymer are melt-mixed at 180 ° C with an extruder to make a temperature-sensitive color-remembering color memory molding resin composition (pellets). ) Was obtained.
Using the pellets, a plate-like body (reversible thermal discoloration layer B22) was molded at a cylinder temperature of 180 ° C. by an injection molding machine.
15 parts of reversible thermochromic microcapsule pigment A, 77 parts of urethane emulsion resin, 2 parts of thickener, 0.5 part of leveling agent, eraser on the surface of the plate-like body, which was previously cooled to -20 ° C or lower to make it blue. A reversible thermochromic ink obtained by uniformly dispersing 0.5 parts of a foaming agent and 5 parts of a cross-linking agent is solid-printed using a 120-mesh screen plate, dried and cured, and a reversible thermochromic layer A21 is provided for counterfeiting. The prevention medium 1 was obtained.
At room temperature (25 ° C.), the anti-counterfeit medium has a blue color due to the reversible thermochromic microcapsule pigment A, and the state is maintained in the room temperature range.
Next, when the anti-counterfeit medium was heated to 58 ° C. or higher, the reversible thermochromic microcapsule pigment A was decolorized and became colorless.
When the colorless anti-counterfeit medium is cooled to −20 ° C. or lower, both the reversible thermochromic microcapsule pigment A and the reversible thermochromic microcapsule pigment B develop colors to prevent purple, which is a mixture of blue and pink. The medium was visible.
When heated again and reaches a temperature of 56 ° C or higher, only the reversible thermochromic microcapsule pigment A is decolorized and becomes pink, and when the temperature is 58 ° C or higher, the reversible thermochromic microcapsule pigment B is decolorized and colorless. It was not possible to return to the initial blue anti-counterfeit medium, and it had a function as an anti-counterfeit medium.
The color difference ΔE ^* _ab between the blue anti-counterfeit medium and the colorless anti-counterfeit medium was 58.0 when measured using a Konica Minolta fluorescence spectrophotometer, product number: FD-7, and the blue anti-counterfeit medium and purple. The color difference of the anti-counterfeit medium was 60.1.
Further, the anti-counterfeit medium also has a function as a temperature indicator for detecting that the temperature exceeds a predetermined temperature or a temperature indicator for detecting that the temperature has fallen below the predetermined temperature.

Example 4
Preparation of Reversible Thermochromic Microcapsule Pigment C (a) 2.0 parts of 1,3-dimethyl-6-diethylaminofluorane as a component (b), 1,1-bis (4-hydroxyphenyl) n- as a component (b) Thermochromic color memory consisting of 5.0 parts of decane, 5.0 parts of 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane, and 50.0 parts of 4-methylbenzyl palmitate as a component (c). A solution obtained by heating and dissolving the sexual composition and mixing 35.0 parts of an aromatic isocyanate prepolymer and 40.0 parts of an auxiliary solvent as a wall film material was emulsified and dispersed in an 8% aqueous solution of polyvinyl alcohol and heated. After continuing stirring, 2.5 parts of water-soluble aliphatic modified amine was added, and further stirring was continued to obtain a microcapsule suspension. The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The average particle size of the microcapsule pigment is 2.4 μm, and the hysteresis characteristics are t ₁ : -3 ° C, t ₂ : 5 ° C, t ₃ : 37 ° C, t ₄ : 43 ° C, ΔH: 39 ° C. It showed the behavior of having, and the color changed reversibly from orange to colorless and from colorless to orange.

Preparation of reversible thermochromic microcapsule pigment D (a) 2.0 parts of 3,3-bis (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide as a component, and 1,1-bis as a component (b) 5.0 parts of (4-hydroxyphenyl) n-decane, 5.0 parts of 2,2-bis (4'-hydroxyphenyl) -hexafluoropropane, 50.0 parts of 4-methylbenzyl palmitate as a component (c) A solution of 35.0 parts of aromatic isocyanate prepolymer and 40.0 parts of auxiliary solvent as a wall film material was mixed by heating and dissolving the thermochromic color memory composition composed of the above in an 8% polyvinyl alcohol aqueous solution. After emulsifying and dispersing and continuing stirring while heating, 2.5 parts of water-soluble aliphatic modified amine was added, and further stirring was continued to obtain a microcapsule suspension. The suspension was centrifuged to isolate a reversible thermochromic microcapsule pigment.
The average particle size of the microcapsule pigment is 2.3 μm, and the microcapsule pigment behaves with hysteresis characteristics of t1: -3 ° C, t2: 5 ° C, t3: 38 ° C, t4: 44 ° C, and ΔH: 40 ° C. , The color changed reversibly from turquoise to colorless and from turquoise to turquoise.

Preparation of anti-counterfeit medium On white synthetic paper as a support, 15 parts of reversible thermochromic microcapsule pigment C that was previously cooled to -20 ° C or lower to turn orange, 15 parts of reversible thermochromic microcapsule pigment D in a colorless state, urethane A 120-mesh screen plate of reversible thermochromic ink made by uniformly dispersing 62 parts of the emulsion resin, 2 parts of the thickener, 0.5 part of the leveling agent, 0.5 part of the defoaming agent, and 5 parts of the cross-linking agent. It was used for solid printing and dried and cured to form a reversible thermochromic layer to obtain an anti-counterfeit medium.
In the anti-counterfeit medium, an orange color due to the reversible thermochromic microcapsule pigment C is visually recognized at room temperature (25 ° C.), and the state is maintained in the room temperature range.
Next, when the anti-counterfeit medium was heated to 43 ° C. or higher, the reversible thermochromic microcapsule pigment C was decolorized and became colorless, and the white color of the support was visually recognized.
When the white anti-counterfeit medium is cooled to -3 ° C or lower, both the reversible thermochromic microcapsule pigment C and the reversible thermochromic microcapsule pigment D develop colors to prevent black anti-counterfeiting in which orange and blue-green are mixed. The medium was visible.
When heated again and reaches a temperature of 43 ° C or higher, only the reversible thermochromic microcapsule pigment C is decolorized and becomes blue-green, and when the temperature is 44 ° C or higher, the reversible thermochromic microcapsule pigment D is decolorized and colorless. It was not possible to return to the initial orange anti-counterfeit medium, and it had a function as an anti-counterfeit medium.
The color difference ΔE ^* _ab between the orange anti-counterfeit medium and the white anti-counterfeit medium was 67.5 when measured using a Konica Minolta fluorescence spectrophotometer, product number: FD-7, and the orange anti-counterfeit medium and black. The color difference ΔE ^* _ab of the anti-counterfeit medium was 75.5.
Further, the anti-counterfeit medium also has a function as a temperature indicator for detecting that the temperature exceeds a predetermined temperature or a temperature indicator for detecting that the temperature has fallen below the predetermined temperature.

Example 5
Preparation of anti-counterfeit medium As a support, 15 parts of reversible thermochromic microcapsule pigment C, 77 parts of urethane emulsion resin, 2 parts of thickener, leveling agent, which was previously cooled to -20 ° C or lower to turn orange on white synthetic paper. A reversible thermochromic ink obtained by uniformly dispersing 0.5 parts, 0.5 parts of a defoaming agent, and 5 parts of a cross-linking agent is solid-printed using a 120-mesh screen plate, dried and cured, and is colored reversible. A thermal discoloration layer C was provided.
Next, on the reversible heat-discoloring layer C, 15 parts of the colorless reversible heat-changing microcapsule pigment C, 77 parts of the urethane-based emulsion resin, 2 parts of the thickener, 0.5 part of the leveling agent, and 0 parts of the defoaming agent. A reversible thermochromic ink obtained by uniformly dispersing 5 parts and 5 parts of a cross-linking agent is solid-printed using a 120-mesh screen plate and dried and cured to form a colorless reversible thermochromic layer D to prevent counterfeiting. I got the medium.
In the anti-counterfeit medium, a pale orange color due to the reversible thermochromic microcapsule pigment C in a colored state is visually recognized at room temperature (25 ° C.), and the state is maintained in the room temperature range.
Next, when the anti-counterfeit medium was heated to 43 ° C. or higher, the reversible thermochromic microcapsule pigment C in the colored state was decolorized and became colorless, and the white color of the support was visually recognized.
When the white anti-counterfeit medium is cooled to -3 ° C or lower, both the reversible thermochromic layer C and the reversible thermochromic microcapsule pigment C contained in the reversible thermochromic layer D develop a color, and a dark orange anti-counterfeit medium is visible. Was done.
When heated again to a temperature of 43 ° C. or higher, the reversible thermochromic microcapsule pigment C decolorizes and becomes colorless, and cannot be returned to the initial pale orange anti-counterfeit medium, and functions as an anti-counterfeit medium. Had had.
The color difference ΔE ^* _ab between the light orange anti-counterfeit medium and the white anti-counterfeit medium was 65.8 when measured using a Konica Minolta fluorescence spectrophotometer, product number: FD-7, which was a light orange anti-counterfeit medium. The color difference ΔE ^* _ab of the dark orange anti-counterfeit medium was 21.1.
Further, the anti-counterfeit medium also has a function as a temperature indicator for detecting that the temperature exceeds a predetermined temperature or a temperature indicator for detecting that the temperature has fallen below the predetermined temperature.

t ₁ complete color development temperature t ₂ color development start temperature t ₃ decolorization start temperature t ₄ complete decolorization temperature ΔH hysteresis width 1 temperature indicator 2 reversible thermal discoloration layer 21 reversible thermal discoloration layer A
22 Reversible thermal discoloration layer B
3 Support

Claims (10)

It comprises a reversible thermochromic layer containing the same thermochromic color memorizing composition, which changes color from colored to colorless, one in a colored state and the other in a colorless state. The complete color-developing temperature t ₁ of the sex composition is a temperature equal to or higher than the complete color-developing temperature t _{1 of the} thermochromic color-memory composition in the colored state, and the temperature-sensitive color-sensitive color memory composition in the colorless state is completely extinguished. The color temperature t ₄ is a temperature equal to or higher than the complete decoloring temperature t _{4 of the} thermochromic color memory composition in a colored state, and the thermochromic color memory composition is hysteresis with respect to the color density-temperature curve. exhibit photochromic colored state and the colorless state shows a characteristic, in the process of temperature increase from the colored state, it begins decolorized to reach decoloring starting temperature t _3, the temperature t ₃ higher than the complete decoloring temperature t ₄ It becomes completely colorless in the above temperature range, and in the process of lowering the temperature from the colorless state, it begins to color when the color development start temperature t ₂ is reached, and is completely in the temperature range below the complete color development temperature t _{1 which} is lower than the temperature t _2. A temperature indicator that shows the hysteresis characteristics that result in a colored state. The temperature indicator according to claim 1, wherein a room temperature range is provided between the color development start temperature t ₂ and the decolorization start temperature t ₃ . The temperature indicator according to claim 2, wherein the normal temperature range is in the range of 5 to 35 ° C. Color difference between the color of the temperature indicator in which one of the thermochromic color memory compositions is colored and the other is colorless, the color of the temperature indicator in which both are colorless, and the color of the temperature indicator in which both are colored ( The temperature indicator according to any one of claims 1 to 3, wherein ΔE ^* _ab ) is 10 or more, respectively. The temperature indicator according to any one of claims 1 to 4, further comprising a support of a reversible thermochromic layer. It is provided with a reversible thermochromic layer containing the same thermochromic color memory composition, which changes color from colored to colorless, one in a colored state and the other in a colorless state, respectively, and the temperature sensitive color memory in the colorless state. The complete color-developing temperature t ₁ of the sex composition is a temperature equal to or higher than the complete color-developing temperature t _{1 of the} thermochromic color-memory composition in the colored state, and the temperature-sensitive color-sensitive color memory composition in the colorless state is completely extinguished. The color temperature t ₄ is a temperature equal to or higher than the complete decoloring temperature t _{4 of the} thermochromic color memory composition in a colored state, and the thermochromic color memory composition is hysteresis with respect to the color density-temperature curve. exhibit photochromic colored state and the colorless state shows a characteristic, in the process of temperature increase from the colored state, it begins decolorized to reach decoloring starting temperature t _3, the temperature t ₃ higher than the complete decoloring temperature t ₄ It becomes completely colorless in the above temperature range, and in the process of lowering the temperature from the colorless state, it begins to color when the color development start temperature t ₂ is reached, and is completely in the temperature range below the complete color development temperature t _{1 which} is lower than the temperature t _2. A temperature indicator that shows the hysteresis characteristics that result in a colored state. The temperature indicator according to claim 6, wherein a room temperature range is provided between the color development start temperature t ₂ and the decolorization start temperature t ₃ . The temperature indicator according to claim 7, wherein the normal temperature range is in the range of 5 to 35 ° C. Color difference between the color of the temperature indicator in which one of the thermochromic color memory compositions is colored and the other is colorless, the color of the temperature indicator in which both are colorless, and the color of the temperature indicator in which both are colored ( The temperature indicator according to any one of claims 6 to 8, wherein ΔE ^* _ab ) is 10 or more, respectively. The temperature indicator according to any one of claims 6 to 9, further comprising a support of a reversible thermochromic layer.

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